Add async instrumentation support

[AndreasPB]

[caspervk]

@trallnag should this be merged?

[Skeen]

Async support would be great

[trallnag]

Is this still relevant? From what I understand the new middleware implementation is async. I did not implement this, so I can't say for sure. In addition I know almost nothing about async Python.

https://github.com/trallnag/prometheus-fastapi-instrumentator/pull/139

[AndreasPB]

We use this branch at work, so it would be awesome to have it on master :)

Edit: I'll try to read through the changes to make sure

[codecov[bot]]

Codecov Report

Merging #61 (b8491ab) into master (e1b2391) will increase coverage by 0.14%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #61      +/-   ##
==========================================
+ Coverage   93.60%   93.75%   +0.14%     
==========================================
  Files           5        5              
  Lines         297      304       +7     
==========================================
+ Hits          278      285       +7     
  Misses         19       19              

Impacted Files	Coverage Δ
...ometheus_fastapi_instrumentator/instrumentation.py	95.52% <100.00%> (+0.28%)	:arrow_up:
...rc/prometheus_fastapi_instrumentator/middleware.py	95.23% <100.00%> (+0.17%)	:arrow_up:

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[trallnag]

I managed to rebase your enhancement into the new middleware. I don't have any tests yet. Can you add examples on how you use async_instrumentation? Of course only if it is still relevant for you.

I will go ahead and merge it into master regardless because the changes don't interfere in any way with existing code.

[Skeen]

... Can you add examples on how you use async_instrumentation?

Hi, we use this feature actively.

The use-case is exactly as with the non-async case:

sync_metric = Info("sync_metric", "Documentation")
async_metric = Info("async_metric", "Documentation")

def sync_function(_: InstInfo) -> None:
    value = sync_metric_getter()
    sync_metric.info({"type": value})

async def async_function(_: InstInfo) -> None:
    value = await async_metric_getter()
    async_metric.info({"type": value})

instrumentator = Instrumentator()

instrumentator.add(sync_function)
instrumentator.add(async_function)

This just adds the option of using async def functions.

[trallnag]

@Skeen, thanks for the example. Adapted it into a unit test

[Skeen]

@Skeen, thanks for the example. Adapted it into a unit test

You're awesome, thank you for the work that you do!

[AndreasPB]

What @Skeen said - Thank you!

One last request, would it be possible to get a release with these changes sometime in the near future, @trallnag?

[trallnag]

@AndreasPB, I'll release it already this weekend